This invention generally involves a locking mechanism for suspending well flow controls in a landing sub in a tubing or casing string disposed in an oil well borehole.
The usual type of locking devices for suspending flow control devices, such as valves, in a landing sub utilizes expandable collet fingers having bevelled shoulders arranged to be expanded outward and locked into matching internal channels in the landing sub or landing nipple. The spring type collets are arranged to flex radially inward when passing through obstructions and when entering the landing sub. When it is desirable to lock the tool in the sub, a sleeve or wedge is driven up inside the spring collets to prevent their inward flexing and to fixedly secure the collet shoulders in the internal sub channel.
A disadvantage of the spring collet type of locks is that they tend to be difficult to set completely, and also that the bevelled shoulders may be pulled out of the locking channels even when set because of the angled sides of the bevel shoulders which do not provide a truly positive abutment in the sub channel.
The present invention provides a positive locking mechanism which utilizes a single, unitary, locking member to overcome the disadvantages of the prior art.